RECOMMENDED ISOLATION DISTANCES FOR THE FIELD MULTIPLICATION OF DIPLOID TUBER-BEARING SOLANUM SPECIES

The sexual propagation of genebank accessions by hand pollination in t he greenhouse is a very expensive and time-consuming routine task. The self-incompatibility of most diploid potato species allows their mult iplication in isolated field plots, which is coupled with the advantag e of the presence of natural pollinators and maintaining a high level of heterozygosity. The aim of this study was to determine the isolatio n distance required for minimizing pollen flow between neighbouring mu ltiplication plots. The Solamum phureja clone IVP48 was used as the po llen donor since it possesses a dominant seed marker ('embryo spot'). The centrally located pollen donor was surrounded by S. phureja recipi ent plots at distances of 10, 20, 40, and 80 m, respectively. The aver age pollen contamination ranged from 0.2% in the plots 80 m from the p ollen donor to 5.1% in those 10 m away. In this study, procedures are suggested which will help to reduce cross-pollination between accessio ns.